Heat exchanger



Oct. 25, 1960 H. M. CAMPBELL 2,957,679

HEAT EXCHANGER Filed June 2, 1955 3 Sheets-Sheet-1 i777 R f Oct. 25, 1960 H. M. CAMPBELL 9 HEAT EXCHANGER Filed June 2, 1955 3 Sheets-Sheet 2 I rap/1 67 Oct. 25, 1960 H. M. CAMPBELL HEAT EXCHANGER 3 Sheets-Sheet. 3

Filed June 2, 1955 E I l IN VEN TOR. 1 /0 ru M CMPBH X.

2,957,679 Patented Oct. 25, 1960 United States Patent-Ofiice HEAT EXCHANGER Huntly M. Campbell, Alton, 111., assignor to Olin Mathiason Chemical Corporation, Alton, 11]., a corporation of Virginia Filed June 2, 1955, Ser. No. 512,655

4 Claims. (Cl. 257-130) This invention relates to a heat exchanger of the multiple parallel tube type as exemplified by automobile radiators, and is an improvement upon the heat exchanger disclosed in the copending application of myself and Leland H. Grenell, Serial No. 175,226, filed July 21, 1950, now US. Patent Number 2,759,247 granted August 21, 1956 and the copending application of John D. Wilkins, Serial No. 495,542, filed March 21, 1955 and now US Patent No. 2,924,437, granted February 9, 1960.

In the aforesaid application of myself and Leland H. Grenell, there is disclosed a heat exchanger wherein a plurality of separate panels, each made from pressure unified sheets of metal so :as to include integral tubes and intervening webs, are arranged together in aligned spaced series, and secured in such relationship by appropriate interconnecting parts. In the aforesaid Wilkins application, it is contemplated to integrate a plurality of panels into one continuous plate, and then to zig-zag fold the plate so that each tube panel constitutes a lap of the fold, and the structure is held together in the appropriate spaced relationship by integral parts of the single plate. The structures disclosed in said applications, and all other such comparable constructions of which I am aware, require the provision of a separate header tank at each end of the tube panels, and connected to the various tubes by an appropriate fluid-tight connection, such as a soldered joint. While the structures disclosed in said applications represent a substantial diminution of the amount of soldering required for assembling a heat exchanger of the character contemplated, it is obviously desirable, and hence it is an object of the present invention, to further eliminate the necessity for such soldering, or other fluid-tight connections, bet-ween the tubes and the header tanks, or chambers, at either end thereof.

The aforesaid objective is accomplished in accordance with the present invention by providing, as :an integral part of the pressure unified sheet from which the several tube panels are formed, a transverse header chamber connected with the various tubes in the panels, and which is, like the integrally connected tube panels of the aforesaid Wilkins application, zig-zag folded to form a continuous serpentine header chamber at the opposite ends of the tube panelsw Another object of the invention is to provide a heat exchanger of the character aforesaid, wherein the shape of the tubes is such as to be readily adaptable for the reception and retention of corrugated fin stock between adjacent panels of the folded structure.

Other objects will become apparent from the following description when read in connection with the accompanying drawings, in which:

Figure 1 is a plan view of a pressure unified plate containing an internal pattern of unconnected areas suit able for the manufacture of the heat exchange member shown in the other figures of the drawings;

Figure 2 is a view in front elevation of an automobile radiator embodying the heat exchange member of the present invention;

Figure 3 is a top plan view of the radiator shown in Figure 2, part being broken away, and part shown in section to reveal the relationship of the parts;

Figure 4 is a sectional view taken along line 44 of Figure 2; a

Figure 5 is a sectional view taken along line 5-5 of Figure 2; and

Figure dis a perspective view of a portion of the plate shown in Figure 1 after the same has been distended, but before folding.

In accordance with this invention, a heat exchange unit with an array of tubes arranged in spaced susbtantially parallel planes is fabricated from a plate of metal formed of two sheets pressure welded or single phase roll welded together with :an intervening pattern of stop-weld material delineating areas in which fluid passageways will be distended by pneumatic or hydraulic expansion. The plate includes not only a series of heat transfer fluid conveying tubes, but also an inlet header passageway and an outlet header passageway. The plate is folded back and forth to provide a series of panels containing the heat transfer tubes. The distended plate from which the unit is made includes two walled distended separation portions defining fluid passageways in the sheet, and also includes welded single walled portions, or unseparated areas, of double thickness as a unitary or monolithic portion of the sheet. The folds of the plate occur at certain of the relatively thick welded single walled portions between panels so as to provide a pleated structure made up of folded areas alternating with tubed panel portions between folds. Elongated unwelded portions in each panel form the heat transfer tubes and these elongated unwelded portions of the panels are formed coextensively at their extremities with transversely extending unwelded portions which form the inlet and outlet header portions which extend across the entire zig-zag folded sheet. Between the heat transfer tubes, the plate is perforated at least at the regularly occurring bends so as to allow a cross stream of fluid, such as air, to pass along the outside of the heat transfer tubes disposed in the panels of the sheet between folds. Each panel may contain a single tube or a number of parallel spaced individual smaller tubes. The opposing walls at the distended tube and passageway portions may be internally welded together at intervals for the purpose of stiffening these portions. While the heat exchange unit of this invention is adapted to constitute an entire heat exchanger, two or more of the units may be assembled to make up a heat exchanger. Since the tube panels are adapted to be set up in spaced substantially parallel relationship, it is desirable that any suitable fin stock, preferably corrugated, be installed between the panels in contiguity with the heat transfer tubes.

The heat exchanger structure of this invention is further characterized by the fact that the Walls of the header passageways, or inlet and outlet channels, are distended out beyond the surfaces of the unseparated areas of the plate to a greater degree than the distended walls of tube passageways of the tube panels. As a result, the cross-sectional area of each of the header passageways is considerably larger than the cross-sectional area of a tube passageway. This enables the header portions in adjacent panels of the zigzag plate to be in abutment, thus producing a more solid construction While the tubes of adjacent tube panels remain spaced to form an open passage for other fluids, such as air, between the spaced panels.

It is preferred that the cross-sectional shape of at least the tube passageways in the panels be substantially flat and oblong. In the specific embodiment hereinafter de-' scribed, both the tube passageways extending down each panel and the header passageways extending transversely across the opposite ends of the panels are of fiat oblong shape, which adapts the unit for advantageous assembly with all its portions, including the header sections as well as the fin stock. A flat oblong passageway cross-section is made practical by the inclusion of the areas of internal reenforcement, and such oblong shape is peculiarly adapted for inclusion of fin stock.

The heat exchange unit consists of elongated tube panels disposed between bent panel interconnecting portions, or folds, formed integrally with the panels. Each panel comprises a portion of a header chamber at each end of the panel and also includes at least one tube passageway forming a fluid connection between the header portions. Each fold or panel interconnecting portion is of elongated configuration, too, and is disposed between the elongated edges of a pair of adjacent panels. Each fold comprises at each end a bent or arcuate portion of a header passageway, and between the header portions each panel interconnecting fold of the zig-zag sheet is perforated with slots, preferably elongated to permit the free passage of a fluid, such as air, over the outside of the walls of the heat transfer tube passageways of the panels. This leaves between each adjacent pair of slots in the fold a bent interconnecting strap between adjacent panels. Thus each header is of serpentine configuration, and consists of a series of the header passageway portions disposed at one end of each of the panels in alternation with a series of the arcuate header passageway portions disposed at the same end of each of the panel interconnecting folds.

The heat exchange unit, especially when it is formed of very thin gage metal, is advantageously mounted in a confining frame, such as one of sheet metal of heavy gage. The frame may be provided with mounting brackets, or the like, by which the unit may be cradled or supported in a desired heat exchanger installation.

The plate shown in Figure 1 is produced from two sheets of metal 1 and 2 which have been pressure unified by the technique disclosed in United States Patent No. 2,690,002 to L. H. Grenell, with a pattern of stopweld material between them. The pattern of stop-weld material is indicated by the stippling of Figure 1, and embraces a plurality of parallel elongated areas 3 intervened by unprotected areas 4. The pattern of stopweld material also includes transverse header regions 5 and 6 across the tops and bottoms, respectively, of all of the elongated areas 3. The pattern of stop-weld material in one of the header regions extends completely to the margin of the plate as shown at 7, but otherwise, the pattern of stop-weld material is completely surrounded by a marginal area 8 unprotected by the stop-weld material. Within the several elongated areas 3, there are islands 9 unprotected by the stop-weld material, and likewise within the header regions 5 and 6, there are islands 10 unprotected by the stop-weld material. The plate shown in Figure 1 is shown in the condition in which it exists after the two sheets 1 and 2 with the intervening pattern of stop-weld material has been subjected to a rolling operation in which the sheets are reduced in thickness, elongated in length, and integrated \at all of the areas 4, 8, 9, and 10, which are unprotected by the stop-weld material.

It is preferred that the tube portions 13 be of oblong cross-section with the separation between opposite walls thereof substantially less than the separation between opposite walls of the header chamber. In this way, the adjacent laps of the header chamber may be brought into contiguity without bringing the exterior walls of the tube portions into contiguity, so that an appropriate space for the circulation of a heat exchange medium, such as air, between the tube portions of the respective panels is maintained.

The provision of the islands 19 t e confines of the respective tube panels tends to induce the oblong overall cross-sectional shape of the tubes, as well as to stiffen and strengthen the tube portions of the respective panels, and to divide the stream of Water or other coolant traversing such tubes into smaller streams. Similarly, the islands 20, at which the header portions are integrated, tend to eliminate non-uniformity in the degree of distention of the header chambers from one panel to the next, and to strengthen and stiffen the header chambers of each panel.

In Figure 4, a sectional view is shown through the portions of the serpentine header where the the islands 20 are located, it being understood that the header chamber is open both above and below the section shown. The section shown at the lefthand end of Figure 3 is, however, taken below the region of islands 20, so that the chamber 15 is there shown to be completely open.

In the sectional view shown in Figure 5, which is taken at three different levels through the tube portion of the panels, the leftmost pair of panels are shown at a section through the islands 9; the middle pair of panels are shown at a section between the islands 9 and the residue of web 14 which is left upon forming the openings 21; and the rightmost pair of panels are shown at a section through the residual metal vertically between openings 21.

Suitably secured in one endmost lap of each header chamber 15 and 16, there is an appropriate fitting 23. The fittings 23 may be secured to the zig-zag folded plate structure in any suitable manner, as by soldering, it being preferred to attach the fitting to the upper header at the diagonally opposite corner of the structure from the point of attachment of the corresponding fitting to the lower header.

While, in the foregoing description, reference has been made to, and the drawings specifically show, the header chamber 15, it will be understood that the header chamber 16 is identical, except that it is upside down with respect to the tubes 13.

Either before or after the plate is completely distended, but after it is at least partially zig-zag folded, suitable fin stock may be inserted between the respective tube panels, as shown at 24. Such fin stock may be corrugated or zig-zag folded in a manner customary in the art, and disposed between the panels in such manner as to present edges athwart the direction of transverse air fiow through the air space between the panels.

Upon completion of the distention and Zig-zag folding of the plate structure, the same may be enclosed within a suitable confining frame 25 which may have lugs 26 appropriately situated for connecting the same in the desired relationship upon the machine in connection with which the heat exchange member is to be used.

From the foregoing description, those skilled in the art should readily understand the construction and operation of the radiator core and realize that it accomplishes the objects of the invention. While the invention has been described in detail with respect to its use as the core of an automobile radiator, it will be readily understood that as a heat exchanger it is adapted to diverse other uses; and while reference has been made to the circulation of liquid through the tubes, and to the transverse passage of air through the spaces between the tube panels, it will be readily understood that other coolant fluids will, under various circumstances, be utilized instead of air or water, or both.

While a complete disclosure of one embodiment of the invention has been given to illustrate the construction and operation of the same, it is not to be understood that the invention is limited to the details of the foregoing disclosure. On the other hand, those skilled in the art will readily understand that the essential features of the present invention may be adapted and applied in other forms, and hence such adaptation and application as does not depart from the spirit of the invention is contemplated by and within the scope of the appended claims.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. In a heat exchanger formed from pressure-welded component sheets having disposed internally between adjacent component sheets a plurality of spaced tubular passageways separated by substantially completely pressure-unified areas, each of said passagesways extending internally across said welded sheets in substantially parallel relationship to each other and terminating short of a pair of opposite edges of said welded sheets, and wherein said welded sheets are zig-zag folded at said areas to provide an aligned series of internally hollow panels in spaced relationship to each other, at least some of said panels containing at least one of said passageways, the improvement which comprises an internal continuous header tube between said adjacent sheets disposed along the marginal areas between one edge of said edges and the terminal portions of said passageways adjacent said one edge with said header tube interconnected to each of said terminal portions, said zig-zag folded sheets having the header portion within each of said panels containing said header tube distended out of opposite faces of said panels to a greater distance away from said faces than the remaining portions of the panels containing said passageways with said header portion being in abutting relationship with a corresponding header portion of adjacent panels and said remaining portions of said panels being held in said spaced relationship by said abutting portions.

2. In the heat exchanger formed from pressure welded component sheets having disposed internally between adjacent component sheets a plurality of tubular spaced passageway systems separated by substantially completely pressure-unified areas, each of said systems extending internally across said welded sheets and terminating short of a pair of opposite edges of said welded sheets, and wherein said welded sheets are zig-zag folded at said areas to provide an aligned series of internally hollow panels in spaced relationship to each other, at least some of said panels containing one of said systems, the improvement which comprises an internal continuous header system between said adjacent sheets disposed along the marginal areas between one edge of said edges and the terminal portions of said systems adjacent said one edge with said header system interconnected to each of said terminal portions, said zig-zag folded sheets having the header portion within each of said panels containing said header system distended out of opposite faces of said panels to a greater distance away from said faces than the remaining portions of the panels containing said passageway systems with said header portion being in abutting relationship with a corresponding header portion of adjacent panels and with said remaining portions of said panel being held in said spaced relationship by said abutting portions.

3. The improvement of claim 2 wherein the folds at said areas include at least one slot therethrough.

4. A heat exchanger comprising a pair of sheets superimposed upon each other and having portions of their adjacent surfaces secured to each other and distended unsecured portions of said sheets defining between said secured portions a pattern of internal fluid passageways with said sheets being zig-zag folded to provide a series of spaced panels interconnected by bent portions of said sheets extending between zig-zag folded edges thereof, a first portion of said pattern forming a system of fluid passageways disposed within at least one of said panels to extend internally across said one panel transversely of said edges and terminating short of said edges, a second portion of said pattern formed into a continuous header system provided between said sheets in said panels and said bent portions longitudinally of said edges, said header system being spaced from said edges in the marginal portions of said sheets between one of said edges and the terminal portion of said passageway system adjacent said one edge with said header system interconnected to said terminal portion, said sheets having the header portion within said panels distended out of opposite faces of said panel to a greater distance away from said faces than the remaining portions of the panels containing said passageway system with said header portion being in abutting relationship with a corresponding header portion of adjacent panels and with the remaining portion of said panels being held in said spaced relationship by said abutting portions.

References Cited in the file of this patent UNITED STATES PATENTS 1,293,868 Murray Feb. 11, 1919 1,792,768 Robitaille Feb. 17, 1931 1,804,083 Berlin May 5, 1931 1,823,788 Dewoitine Sept. 15, 1931 2,051,277 Stevens Aug. 18, 1936 2,200,426 Lehman May 14, 1940 2,212,481 Sendzimir Aug. 20, 1940 2,349,695 Beane May 23, 1944 2,448,648 Zideck Sept. 7, 1948 2,462,136 Smith Feb. 22, 1949 2,582,358 Schoellerman Jan. 15, 1952. 2,662,273 Long Dec. 15, 1953 2,673,542 Smith Mar. 30, 1954 2,690,002 Grenell Sept. 28, 1954 2,759,247 Grenell et a1 Aug. 21, 1956 2,848,200 Jacobs Aug. 19, 1958 2,924,437 Wilkins Feb. 9, 1960 2,926,003 Pulsifer Feb. 23, 1960 FOREIGN PATENTS 673,311 Great Britain June 4, 1952 

